The headlights on the Model S do not require those little stickers or any adjustment to allow you to travel between the UK and the rest of Europe.

Back in October 2013 when I first received my Model S I spent quite a lot of time with Tesla on this issue.
The people in Tilburg very kindly setup up a headlight control to provide evidence should I ever be stopped by the UK police.

I have been asked by members of the forum to share the photos I took that day.

The first is from the display from my Model S headlight using the control box to indicate where the light shines relative to a control line:
The second is the actual headlight control box used to measure my car's headlight.

I have had no problems on driving on dipped beams and so far no comments from the UK police.